(a) Field of the Invention
The present invention relates to an improved method for preparing methacrolein through gas-phase catalytic oxidation of isobutylene or tertiary butanol with molecular oxygen and an improved method for preparing a catalyst for use in the catalytic oxidation reaction
(b) Description of the Prior Art
There have conventionally been proposed a variety of catalysts used in the preparation of methacrolein through gas-phase catalytic oxidation of isobutylene or tertiary butanol with molecular oxygen and, in particular, there have been many proposals concerning those comprising one or both of Co and Ni, and at least one element selected from the group consisting of K, Rb and Cs in addition to Mo, Bi and Fe as essential catalyst components among others In addition, there have recently been proposed those comprising an additional component such as Sb or Mg other than the foregoing catalyst components in order to enhance the quality of the catalysts (see, for instance, Japanese Unexamined Patent Publication (hereinafter referred to as "J.P. KOKAI") Nos. Sho 63-107745 and Sho 63-122642). However, these catalysts conventionally proposed are still insufficient in various catalytic properties such as catalytic activity, stability, lifetime and selectivity to methacrolein and there still remains room for further improvement.